An Approach to Evaluation of Ecological Status of Populations of Forest-Nesting Birds (Passeriformes and Piciformes)
S. E. CHERENKOV
Severtsov Institute of Ecology and Evolution of the RAS, 119071, Moscow, Leninsky аve., 33
Keywords: гнездящиеся лесные птицы, площадь местообитания, емкость местообитания, пространственная структура популяции, оценка экологического состояния, forest-nesting birds, area of habitat, carrying capacity of habitat, spatial structure of population, estimation of ecological status, Passeriformes, Piciformes
Abstract
A 13-year study of forest-nesting birds (orders Passeriformes and Piciformes) was conducted at five constant census areas in European Russia, the Caucasus and mountains of Southern Siberia. Nesting individuals were mapped at each census area during two or more nesting periods. Nesting densities for each species were estimated. The raster maps of spatial allocation (MSA) at the scale 50 x 50 m of the raster grid were obtained for each species. The degree of spatial conservatism (DSC) for each local population was inferred from the pairwise comparisons of the specific MSAs obtained in the same area in different years with the use of the Gamma rank correlation method. This index characterizes connection between the population and the habitat. Based on 5-year observations in the particular census area, the areas of habitats were estimated and mean DSC values were obtained for each of 18 model species. Using the model Y = 117 - 103.5 X ( Y area of habitat, X DSC; R = 0.84, p < 0.01) it was demonstrated that (axis Y ) and the mean estimates of DSC (axis X ) were calculated by the five-year rows on one experimental plot for 18 bird species. With the help of the model ( Y = 117 - 103.5 X ; R = 0.84 p < 0.01), it is shown: under conditions of almost complete saturation, when population uses almost entire area of available habitats and maximum carrying capacity of habitat is almost achieved, the total area occupied by the individual nesting home ranges of the particular species is in an inverse linear relation from DSC estimates. Based on this model, it is possible to calculate the maximum carrying capacity of habitat for each species from its DSC value. Maximum nesting density for each species in the particular census area was calculated based on its DSC values and mean size of its nesting home range. The ratio between observed and maximum nesting densities allowed to estimate the degree of saturation of carrying capacity of habitat and the population status of the particular species under different environmental conditions.
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